A side airbag device that protects an occupant from an impact in the event of side impacts is generally provided inside a lateral portion close to the window side of an occupant seat backrest (hereinafter referred to as a seat back) of a seat.
Such a side airbag device has a configuration in which an inflator operates according to a signal output from a sensor that has detected an impact in the event of a side impact to generate inflation gas and an airbag is deployed by the generated gas.
In a side airbag device having such a configuration, an inner tube that changes the direction in which gas discharged from an inflator flows is generally provided. For example, see the diffuser of Japanese Patent Application Publication No.
The inner tube is typically formed in a tubular form by sewing or melt-bonding. When these sewing portions or melt-bonding portions are directly exposed to the gas discharged from the inflator, the heat-associated damage may increase.
However, conventionally, the above-mentioned problem has not been addressed.